/Engine/Plugins/Animation/ControlRig/Source/ControlRig/Public/Rigs/RigHierarchy.h
Sets the weight of a parent below a multi parent element
Returns true if changing the weight was successful
bool SetParentWeight ( [FRigBaseElement](API\Plugins\ControlRig\Rigs\FRigBaseElement) * InChild, int32 InParentIndex, [FRigElementWeight](API\Plugins\ControlRig\Rigs\FRigElementWeight) InWeight, bool bInitial, bool bAffectChildren )